Hamburg 2016 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 27: BSM Suchen III (Vektorartige Quarks)

T 27.8: Vortrag

Montag, 29. Februar 2016, 18:30–18:45, VMP6 HS B

Search for Singly Produced Vector-Like Down-Type Quarks with ATLAS — •Laura Rehnisch, Janet Dietrich, and Heiko Lacker — Humboldt-Universität zu Berlin

Vector-like quarks are predicted in several models, e.g. composite Higgs models. Due to relatively high mass limits from previous searches and the limited phase space for pair-produced heavy quarks, it is indicated to investigate single production of these particles. A search for down-type vector-like quarks decaying to a W boson and a top quark, conducted on the 8 TeV dataset recorded in 2012 with the ATLAS detector, will be presented. Two models, a vector-like quark, B, and an excited quark with vector-like couplings, b^*, have been investigated. The presented and recently published results were obtained using single-lepton and dilepton final states, while the presentation will focus on single-lepton events in which boosted decay topologies of the heavy quarks are used. This increases the sensitivity, as jets from hadronically decaying W’s and tops are likely to be merged. In the absence of a significant excess of the data over the expected background, cross-section limits were set. Excited vector-like quarks with masses below 1.5 TeV are excluded.